How do early-type galaxies form and evolve? How do the properties of these galaxies depend on their dark matter halo? I address these questions using strong gravitational lensing as my main investigation tool. I joined the Kavli IPMU, so that I could look for new strong gravitational lenses in the Hyper Suprime-Cam (HSC) survey. Thanks to its very large field of view, HSC will allow us to find more strong lenses than what has ever been possible with any other survey.